1. Field of Art
This invention relates to the improvement of machines used in the harvesting of corn. More particularly, it relates to a stalkroll on a corn head.
2. Description of Prior Art
Mechanical harvesting of corn has taken place for decades. However, efforts continue to make corn harvest operations more efficient and effective. A corn harvester generally includes a corn head which removes the ears from the stalks. The ears of corn are then fed into a separator or thresher which separates the grains of corn from all other materials. A corn head actually consists of several corn head assemblies, one for each row which is being harvested in a single pass over the field. As the corn head moves forward, the corn plants in each row enter the forwardly extending channels. Generally the corn head includes a stripper plate with a slot which is wide enough to receive the corn stalk, but not wide enough for the stalk and an ear of corn to pass through. As the stripper plate moves forward, it exerts a forward and upward force on the ear.
Below the snapping plate in each corn head unit are a pair of stalkrolls the axis of which are parallel to the stripper plate slot and on each side of said stripper plate slot. These rolls rotate in opposite directions to one another engaging the stalk below the stripper plate. The directions of rotation are such as to exert a downward and rearward force on the stalk relative to the stripper plate. The generally opposing forces exerted by the rolls and plate on the stalk and ear snaps off the ear from the stalk. The ears and any trash are transported into the harvester or combine for further processing while the stalk generally remains rooted in the ground.
Stalkrolls generally have conical front ends (sometimes referred to as front augers) to provide a space for entry of the stalk and cylindrical rear ends (sometimes referred to as a fabricated stalkroll) which engage the stalk. The front end may be provided with helical flutes wound in opposite directions to drive the stalk rearwardly relative to the stripper plate. Usually the fabricated stalkrolls have circumferentially spaced, axially extending and radially projecting flutes which engage the stalk. The flutes on each roll are ordered in a manner so that the flutes intermesh in the manner of gears.
In conventional farming, the soil is tilled after the crop is harvested in the fall in order to break up the roots and stalks left in the field and again before planting of the next crop to provide loose soil for receiving the seed. Low till techniques seek to minimize the number of tillings in order to save on fuel costs for machinery, extend the life of machines, enable larger acreage to be tilled and save on labor costs by allowing for the same or smaller work force. Less tillage minimizes soil erosion and pollution of water in wells, aquifers and waterways. Less tillage minimizes the runoff of plant nutrients, unused commercial fertilizers, and herbicide residues. Less tillage and no till techniques, in particular, are believed to improve moisture retention in the soil aiding future crops because the residue left on the ground with these techniques acts as a mulch. The composting effect of the residue after it has decomposed may in the long-term reduce the need for commercial fertilizer. Low till and no till techniques are encouraged or required on some acreage by laws and regulations.
Depending on the tilling technique desired, it may be preferable to use a different stalkroll. For example, the flutes on a low till or no till acreage may be sharper than the flutes used on a stalkroll on conventional acreage. Sharper flutes or knives on a stalkroll will cut the stalk leaving this residue in a better position to decompose. However, to convert the flutes or knives on an existing stalkroll is a difficult and time-consuming task. Depending on the design, anywhere from 6 to 28 bolts per pair of stalkrolls must be removed. Further complicating the situation because stalkrolls are clamped to a drive shaft, rust will hold the stalkroll onto the shaft, requiring force to remove the roll. Further, many stalkrolls are a single cast design where the fabricated stalkroll and front auger are a single unit. However, the flutes on the fabricated stalkroll are the portion which wear down the quickest. Hence, a perfectly good front auger is disposed of while replacing a worn fabricated stalkroll flute or knife.
The prior art illustrates these and other deficiencies. Originally, the stalkrolls required a bearing support between the front auger and fabricated stalkroll as illustrated in U.S. Pat. No. 4,219,919 ('919). However, the bearings were prone to damage and failure if dirt entered the bearings. Furthermore, leaves and husks would tend to get caught and damage the bearing and bearing support elements. Bearing failure would ultimately result in the entire stalkroll failing. Another early stalkroll design is shown by U.S. Pat. No. 3,982,385 ('385). In this design, flutes were bolted directly to the drive shaft. This approach required a large number of bolts making replacement of the knives or flutes time consuming. Recently, the industry has started to use a cantilevered stalkroll and driving mechanism. The conventional stalkroll design in a cantilevered stalkroll system involves clamping two semi-circular halves horizontally around a centrally located drive shaft. U.S. Pat. Nos. 5,404,699 ('699) and 5,040,361 ('361) disclose such an approach. Another difficulty with replacing any stalkroll is the occurrence of rust between the fabricated stalkroll and the drive shaft. Moisture frequently builds up between the stalkroll and drive shaft causing rust, further causing the stalkroll to adhere to the shaft. This adherence to the drive shaft makes removal of the stalkroll even more difficult. '361 has attempted to overcome this problem by a threaded socket (79) at the pinnacle of the front auger for the insertion of a removal device for forcing the shaft from the stalkroll. A final difficulty with all stalkrolls involves the maintenance of proper timing between a pair of stalkrolls. If the fabricated stalkrolls become misaligned, the flutes on the opposing stalkroll will improperly cut the stalk. In certain designs, a misalignment will result in catastrophic damage to the stalkroll. Patents '385 and '699 require perfect alignment in order to be effective in cutting stalks.
Consequently, the need exists for a stalkroll which is easy to remove from the drive shaft, which requires fewer attachment devices and for which the flutes can be easily replaced depending on the desired tillage conditions or wear of the flutes. It would be desirable for a stalkroll for which alignment between a pair of stalkrolls is simple.